Glow discharge tube



IM 193$ P. G. WELLER GLOW DI SCHARGE TUBE Filed Sept. 5, 1930 w P T U 0 INWENTUR m W J. ,4 HTTMNEY Patented Apr. 21, 1936 UNITED STATES PATENT OFFICE GLOW DISCHARGE TUBE York Application September 6 Claims.

My invention refers to a method of and apparatus for controlling current in an electric circuit and more particularly relates to methods of and apparatus for operating relay tubes, for the purpose of exercising an electric action through a release or suspension of electric current, by virtue of a sensitive impression of a magnetic field.

My relay consists, in general, of a specially constructed tube, of a type similar to the well-known glow discharge tubes, except that it has a, hot cathode or filament and another cooperating electrode.

The object of my invention is to provide a novel tube of this type as a sensitive relay for miscellaneous purposes.

Another object of my invention is to provide a novel method for operating such a, tube as a sensitive relay for varying the electric current through definite values, in response to controlling impulses.

Still another object of my invention is to utilize a tube of this nature as a cut-off switch, as a control element for elevators or trains, or as an amplifier for voice currents, or other electrical eflects.

A further object of my invention is to utilize a tube of this nature as a converter from direct current to alternating current.

I have described my invention with reference to the figures.

Figure 1 illustrates the general structure of the relay, in accordance with my invention.

Figure 2 is explanatory of the theory of operation of my invention.

Figure 3 is a circuit adaptation of my invention for controlling electrical current.

Figure 4 is a circuit adaptation ofmy invention for the conversion of direct current into alternating current.

Figure 5 is an adaptation of my relay to control of elevators.

The relay, constructed in accordance with my invention, consists of a vessel with an atmosphere of rarifled gas, or vapor, through which an electrical discharge is passed between two electrodes. One of these electrodes is arranged to be heated and, therefore, becomes suitable for emitting the electrons, equivalent in its operation to a cathode of an electronic tube. However, my tube is not entirely electronic, as it contains a gaseous or vaporous atmosphere, which is subject to ionization and has, therefore, a relatively large current, commonv to this type of device.

On the other hand, the fact that a heated filament is utilized for a cathode permits a voltage drop through the tube which may be of the order 3, 1930, Serial No. 479,578

of 8 to volts, or, under certain circumstances, as low as 1 volt, compared to a voltage drop of 300 or more, which is generally present with cold electrodes.

In the preferred form of my invention, I have utilized mercury vapor, which is derived from a pool of mercury inside of the tube and is held at a certain pressure by the operating temperature. On the other hand, I may also use gases and, in particular, rare gases, such as helium, neon, or argon, at pressures preferably between 1 and 50 microns. The advantage of using mercury vapor, or rare. gases, is that they do not attach or combine with any of the other elements inside the vessel;

As shown in Figure 1, an evacuated vessel I is provided with a cathode, consisting of a heater filament 2, having a deposit of electron emitting substance, such as is well known in the art of manufacture of thermionic tubes. This deposit maybe either directly applied to the filament, or be on the surface of a metallic sheet 3 surrounding the heater and separated from it by a suitable insulation. I have shown leads brought out for the heater and for the cathode, such as 4, 5, 6, respectively. I have also shown an anode element 1, which may be either a wire or a plate, at a suitable distance from the cathode and with a lead connection 8 brought out of the vessel.

For the proper operation of a tube of this nature as a relay, I have found that it is preferable to use a gas filling, for instance, such as the mercury vapor with which the pressure of the vapor will be somewhat dependent on the temperature. Other gases may also be used as the control phenomena may be obtained at different pressures and with different gases, although its particular exhibition will be somewhat dependent on these functions.

The control effect on this tube is exercised by means of a magnetic field, such, for instance, as that produced by permanent magnet 9, by passing its field in the neighborhood of the cathode and over the discharge path. I have discovered that such a field should be applied to the discharge path approximately at right angles to it and to the hot cathode, which, for this purpose, is preferably elongated in one direction. If the magnetic field is applied from one electrode to the other, the current passing through the tube is, in general, increased. If the magnetic field is, however, applied at right angles to the direction from the cathode to the anode, then the discharge, in general, is decreased or completely extinguished. The. variation of the discharge current may be made gradual, either by gradual variation of the strength of the field, or by the variation of its direction.

I have shown in Figure 2 a diagram explanatory of the theory of operation of my relay. The cathode 3 is shown emitting electrons in various directions and a magnetic field represented by vertical lines I 0. Each of these lines of force will tend to spin the adjacent electrons about itself as the electron moves along the lines of the field, causing the electrons to travel in a spiral path, as indicated at II. If the field is strong, such a spinning is of very small circumference, while if the field is weak, the spinning may be of a wide radius, as indicated at I2.

Under normal operation of the tube; that is, without the exercise of the magnetic field, there would be a space charge formed in the space between the cathode and the anode, except for the fact that the gaseous filling inside the tube is subject to the ionization by collision and a consequent destruction of the space charge, thus releasing a powerful flow of electrons from the cathode to the anode and, in addition, a fiow of such gaseous ions as may be formed through the collision with the electrons.

If the electrons are spun around a restricted path, as indicated at H, the destruction of the space charge may be reduced, due to this restriction, since collision of electrons with gaseous molecules and a resultant ionization will occur less frequently. I have also observed that the discharge is deflected in the direction of magnetic field, as is indicated by a luminous glow along the lines of magnetic force. This luminous glow will follow the magnetic lines and by turning these latter in one direction or another, the discharge may be directed towards the other electrode, or else deflected away from it. There is, consequently, a reduction of the flow of current, especially so in the direction at right angles to the magnetic field; that is, the current flow to the indicated anode 1. On the other hand, this field may not be strong enough to destroy the space charge along the magnetic field and by concentrating all the electrons in that direction, it may increase the flow of current to an anode indicated in its position as at m. Such a theory would explain the apparent results of my tests, which, in addition to the above effects of the magnetic field on the current passed by the tube, also shows an intensification of the luminous glow along the path of. the magnetic field, until this, magnetic field is so strengthened that the whole luminous glow disappears, indicating the disappearance of ionization by collision. If the intensified streamis direct from the cathode to the anode, (as when using 1a in Figure 2), then the current will be found increased. If, however, the intensified glow is direct at right angles to the path between the cathode and the anode (as in Figure 2, when anode I is used), then the current will be found materially reduced, until it is entirely wiped out by the cessation of ionization. The presence of the hot cathode in such a tube is the cause of the emission of a powerful electronic stream sufficient to reduce the voltage drop to an extremely low value, with a considerable flow of current and giving the electric state and conditionwhich is susceptible to the control exercised in accordance with my invention.

Although I have described fully and suggested a theory of the operation of this relay tube, I wish it to be understood that the art in this field is in an experimental stage and the particular theories are not as yet sufiiciently definite to form a basis for positive statements. I wish it to be understood that I am referring in this specification to definite experimental results obtained with a type of tube invented by me and the utilization of such a tube in suitable circuits and not to any particular theory of operation of such a tube.

I have shown in Figure 3 a tube of the type described in connection with Figure l and illustrated in the plan as glass or quartz envelope I, with the heater 2, cathode 3 and anode 1. I have shown the leads 4 and 5 connected to the heater secondary I3 of a transformer 14, supplied with alternating current to its primary I5. I have shown the cathode lead 6 connected to the secondary IS; the anode lead 8, together with the lead I T from the transformer, goes to an output circuit. For a practical operation of my relay, I have found that the winding l6 may be designed for a voltage as low as 15 or 20, the internal drop due to the passage of the current through the tube being of the order of 10 volts, or less. Of course, higher voltages for this winding are also possible and for any particular purpose the design and the voltage should be chosen in accordance with the requirements. The figures given are for illustration only. By the use of this type of relay, with the voltage of the secondary 15, of say around 20, a usable current of as much as one-half of an ampere could be secured from a cathode heated with about 5 watts input.

I have also shown in this diagram a magnet 9 located at right angles to the path between the cathode and anode, with a winding ill, by means of which this magnet may be energized or controlled in its intensity, if necessary. The winding l8 may also be connected to the output of a circuit, the energy voltage or current of which is to be amplified, while the output leads 8 and I! may lead to the utilization circuit, or to a further mechanical control relay circuit.

I have shown in Figure 4 diagrammatically an arrangement suitable for conversion of direct current into alternating current, by means of a relay tube, in accordance with my invention. The tube is illustrated as item I, carrying a heater 2 with emitting cathode 3 and a number of anodes, such as 112, 1b and 1c, located in different directions relative to the cathode and preferably spaced at equal angular distances from each other. If I apply to a tube of this nature a magnetic field, as, for instance, by means of the pole pieces l9 and 20, the flow of current to some of the anodes, for instance, to anode 1c, will be increased, while that to the electrodes la and lb will be reduced. By providing a mechanical arrangement for rotating the pole pieces l9 and 20 around the tube, such increases of discharge current can be passed from one anode to another in succession. I have illustrated diagrammatically such a mechanical arrangement, although it will be evident to those skilled in the art that any other mechanical arrangement which accomplishes the purpose of rotating the magnetic field relatively to the tube, or vice versa, may be utilized. In the arrangement shown, I have indicated a rotating yoke 25,

which may be arranged between suitable guide rolls 25 and with an internal toothed surface 21, which is cooperating with a pinion 28, in such a manner as to rotate the yoke around a central point, in which the tube I is located. The pinion 28 may be propelled by a suitable motor 29. if

necessary, with a reduction gear to secure the necessary speed. As an alternative arrangement, I may hold the pole pieces in a stationary position and provide a rotating mechanism for the tube with suitable slip rings for the various connections. I have, however, shown connections from the source of direct current 2| to the cathode 3 and to the star point 22 of a primary of a threephase transformer 23. The three primaries 23a, 23b and 23c are connected respectively to the three anodes Ia, lb and 1c. The star or delta connected secondary may lead directly to an output circuit.

While I have shown in these diagrams some preferred forms with the utilization of the relay tube, in accordance with my invention, it will be evident that these forms of utilization can be changed in accordance with the requirements of the particular art in which it is utilized. Thus, for instance, for an elevator control, I have shown in Figure 5 a relay tube I, in accordance with my invention, mounted in a compartment 30 in the shaft of the elevator 3|. The elevator cage 32 may carry a magnet 9 with the energizing winding [8, said energizing winding to be connected to the control push buttons on the elevator cage, or at the different floors, while the output of the relay tube I may be connected to the control switches for the motor, pulling the cage up or down. By this arrangement, if the cage moves and approaches the position at which it is to stop, the magnet 9, if energized, exercises its action through the relay tube l on the control switches, by means of which the cage is stopped at the required floor level.

A similar arrangement may be utilized for train controls, or for other control purposes, where one moving object has to be stopped at certain positions.

A circuit arrangement, such as illustrated in Figure 3, is well adapted for electric impulse amplifications, while the circuit illustrated in Figure 4 is suitable for conversion of direct current into alternating currents of single phase or polyphase nature and, since the limitations of the current and voltage imposed by the usual type of thermionic tubes has been removed in th structure of my tube, it is possible to design such converters to handle energy with a heavier current at relatively low voltage, as compared with what is now possible for the same type of apparatus.

Having fully described my invention, what I claim as new is as follows:-

1. In a control system for electric current, a control relay tube comprising an envelope, a gaseous atmosphere therein, a solid heated cathode in said envelope, a cooperating anode in said envelope, the pressure of said atmosphere being such as to substantially neutralize the space charge of the electron emission from said cathode through ionization, said cathode and said anode being so designed and located relative to each other that the paths of the discharge carriers therebetween are short compared to the lengths of the electrodes to produce electron streams substantially parallel to each other, and a magnet exercising a magnetic controlling field component on said relay tube at substantially right angles to the paths of said discharge carriers to control the ionizing effect of the electrons emitted by said cathode whereby the output current from said anode and cathode and a source of electric current may be controlled.

2. In a converter from direct current to alternating current, a relay tube comprising an envelope, a gaseous atmosphere therein, a heated cathode within said envelope, a multiplicity of anodes in said envelope, the gaseous atmosphere in said tube having a pressure to normally substantially neutralize the space charge effect of the electron emission from said cathode through ionization, said cathode and said anodes being so designed and disposed relatively to each other that the paths of the discharge carriers therebetween are substantially parallel to each other, circuits for said anodes including a source of direct current and elements cooperating with an output circuit, a controlling magnetic field impressed on said relay, and means whereby the direction of said magnetic field can be varied from a position of substantially right angle to the paths of the discharge carriers between said cathode and one of said anodes to a position substantially parallel to the paths of the discharge carriers between said cathode and said anodes and successively and periodically with respect to separate concentric anodes to vary the current output through the respective anodes to create alternating currents in said output circuits.

3. A gas discharge relay comprising an envelope; an elongated solid thermionic cathode and an anode therein said cathode and said anode being disposed substantially parallel to each other and placed relatively close to each other compared to their lengths to secure substantially parallel paths of the discharge carriers therebetween; a gaseous atmosphere there-in of reduced pressure capable of neutralizing the space charge effect of the electron discharge from said cathode to said anode when subjected to ionization by electron impact; and means for exercising a magnetic field component of varying intensity in accordance with controlling signals upon the electron discharge substantially at right angles to the direction of the discharge current, the intensity of said field being of such value as to control the ionizing effect of the electrons in accordance with variations of field strength.

4. A discharge device comprising an envelope; an indirectly heated solid thermionic cathode of elongated shape and an anode therein, said cathodeand anode being disposed substantially parallel to each other and in relatively close proximity compared to their lengths; a gaseous atmosphere therein of reduced pressure and capable of substantially neutraliziing the space charge effect of the electron discharge from said cathode to said anode when subjected to ionization by electron impact; and means for exercising a magnetic field of varying field strength upon the electron current substantially at right angles to the electron path, the magnitude of said field being such as to control the diameter of the spinning circles of the electrons around the magnetic lines of force in accordance with field strength variations for varying the degree of ionization of said gas atmosphere.

5. A discharge relay comprising an envelope; an elongated solid thermionic cathode and an anode therein, said cathode and said anode being disposed substantially parallel to each other, and spaced in relatively close proximity compared to their lengths, a gaseous atmosphere therein of reduced pressure capable of substantially neutralizing the space charge eifect of the electron discharge from said cathode when subjected to ionization by electron impact; and means for exercising a magnetic field of varying field strength upon said electron discharge substantially at right angles to the direction of the electron stream and of such value as to vary the path of the electrons moving around the magnetic lines of force.

6. A discharge relay comprising an envelope; a solid cathode of elongated shape to furnish a substantially constant electron supply and a positive electrode therein; said cathode and said anode being disposed relatively close to each other compared to their lengths to obtain substantially parallel paths of the discharge carriers therebetween; a gaseous atmosphere of reduced pressure capable of substantially neutralizing the space charge effect of the electron discharge from said source when subjected to ionization by electron impact; and means for exercising a magnetic field of varying strength upon said electron discharge substantially at right angles to the path of travel of the electrons, said field being of such magnitude as to control the ionizing effect of said electrons in accordance with field strength variations.

PAUL G. WEILLER. 

